Analysis of the Kidney–Brain Axis via the Fractional Amplitude of Low-Frequency Fluctuation in Patients with Diabetic Nephropathy

Background Central neuropathies caused by diabetic nephropathy (DN) share similar characteristics. The present study aimed to analyze the changes in brain function of patients with DN based on the kidney–brain axis. Methods The study population consisted of patients with DN and healthy controls (n = 23 per group). Brain resting-state functional magnetic resonance imaging examination was performed on all participants, and the fractional amplitude of low-frequency fluctuation (fALFF) values were calculated. The diagnostic authenticity was assessed through receiver operating characteristic curves using sensitivity, specificity, and Youden index. Statistical analysis included Pearson's correlation between mean fALFF values and DN data. Results The imaging analysis revealed that DN patients exhibited lower fALFF values in the right cingulum anterior segment (RCA) and left cingulum middle segment, and increased fALFF values in the right cingulum middle segment compared to control subjects. The correlation analysis demonstrated that mean fALFF values in the RCA correlated with the estimated glomerular filtration rate in DN patients. Conclusions The research findings demonstrated significant differences in fALFF values in the default mode network and visual cortex-related areas. These observations may be highly valuable for understanding the kidney–brain axis mechanisms of DN, as well as the associations between diabetic microvascular complications.